SkekSo was the first Skeksis Emperor, and counterpart to urSu the Master. His reign was initially a benevolent one. He invited Gelflings into the Castle of the Crystal to serve in his court, and held tournaments, which he invariably won. However, 800 trine after the Great Division, his character changed, and he began ordering the enslavement of both Gelflings and Podlings. SkekTek the Scientist later invented a method of using the beams of the Dark Crystal to extract the essence from prisoners. This essence was reserved solely for skekSo, who used it to rejuvinate himself. When skekSo learned of the prophecy that foretold that a Gelfling would end the Skeksis' rule, he ordered their complete extermination, thus beginning the Garthim War.[2]

During the Garthim Wars, skekSo elevated skekLach the Collector to the position of court favourite, in light of his successful Gelfling acquisition strategies, not knowing that the Collector intended to eventually depose him. SkekLach began to secretly withhold the Emperor's Gelfling essence, and blamed the shortage on his rival, skekVar the General, whom skekSo ordered to cooperate with the Collector completely.[1] SkekSo's favouritism of skekLach caused skekSil the Chamberlain, a former court favourite, to plot against skekLach. The Chamberlain discovered skekLach's secret, and openly accused him in front of the Emperor during the Battle of Bah-Lem Valley, and challenged the Collector to Trial by Fire. SkekSo presided over the Trial, which the Collector won. Despite skekSil's protests, skekSo refused to listen to his accusations, and ordered him to keep quiet or face the consequences.[3]

After the end of the Garthim Wars, skekSo's health began to rapidly deteriorate. With the Gelflings all but exterminated, he could no longer rely on Gelfling essence to maintain his vigour. In desperation, he sought to prolong his life with elixirs and enchantments, but to no avail.[2] His fate was sealed when, in his weakened state, he failed to attend a Ceremony of the Sun which would have given him enough power to live up to the Great Conjunction, which would have granted him a further nine hundred and ninety-nine and one trine of life. He died surrounded by his followers, all eagerly awaiting his death.[4]

His remains were gathered by skekOk the Scroll-Keeper and wound into cerements and placed into a black casket. The three highest-ranking Skeksis, skekSil, skekZok and skekUng, carried the casket to the mausoleum, with the other Skeksis following in single file. The three had previously argued over who should take the foremost corner of the casket, and managed to come to a compromise which all knew would not outlast the funeral. The casket was placed onto a catafalque, and its contents were cremated.[4]